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author | Chris Torek <chris.torek@gmail.com> | 2020-06-12 16:19:59 +0000 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2020-06-12 10:53:44 -0700 |
commit | 8bfcb3a690126e6222f0d4f7012b0f68bb748018 (patch) | |
tree | 23e39a459c38a0cc16a14c17ba87836bc5079f98 /t | |
parent | t/t3430: avoid undefined git diff behavior (diff) | |
download | tgif-8bfcb3a690126e6222f0d4f7012b0f68bb748018.tar.xz |
git diff: improve range handling
When git diff is given a symmetric difference A...B, it chooses
some merge base from the two specified commits (as documented).
This fails, however, if there is *no* merge base: instead, you
see the differences between A and B, which is certainly not what
is expected.
Moreover, if additional revisions are specified on the command
line ("git diff A...B C"), the results get a bit weird:
* If there is a symmetric difference merge base, this is used
as the left side of the diff. The last final ref is used as
the right side.
* If there is no merge base, the symmetric status is completely
lost. We will produce a combined diff instead.
Similar weirdness occurs if you use, e.g., "git diff C A...B D".
Likewise, using multiple two-dot ranges, or tossing extra
revision specifiers into the command line with two-dot ranges,
or mixing two and three dot ranges, all produce nonsense.
To avoid all this, add a routine to catch the range cases and
verify that that the arguments make sense. As a side effect,
produce a warning showing *which* merge base is being used when
there are multiple choices; die if there is no merge base.
Signed-off-by: Chris Torek <chris.torek@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 't')
-rwxr-xr-x | t/t4068-diff-symmetric.sh | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/t/t4068-diff-symmetric.sh b/t/t4068-diff-symmetric.sh new file mode 100755 index 0000000000..31d17a5af0 --- /dev/null +++ b/t/t4068-diff-symmetric.sh @@ -0,0 +1,91 @@ +#!/bin/sh + +test_description='behavior of diff with symmetric-diff setups' + +. ./test-lib.sh + +# build these situations: +# - normal merge with one merge base (br1...b2r); +# - criss-cross merge ie 2 merge bases (br1...master); +# - disjoint subgraph (orphan branch, br3...master). +# +# B---E <-- master +# / \ / +# A X +# \ / \ +# C---D--G <-- br1 +# \ / +# ---F <-- br2 +# +# H <-- br3 +# +# We put files into a few commits so that we can verify the +# output as well. + +test_expect_success setup ' + git commit --allow-empty -m A && + echo b >b && + git add b && + git commit -m B && + git checkout -b br1 HEAD^ && + echo c >c && + git add c && + git commit -m C && + git tag commit-C && + git merge -m D master && + git tag commit-D && + git checkout master && + git merge -m E commit-C && + git checkout -b br2 commit-C && + echo f >f && + git add f && + git commit -m F && + git checkout br1 && + git merge -m G br2 && + git checkout --orphan br3 && + git commit -m H +' + +test_expect_success 'diff with one merge base' ' + git diff commit-D...br1 >tmp && + tail -n 1 tmp >actual && + echo +f >expect && + test_cmp expect actual +' + +# The output (in tmp) can have +b or +c depending +# on which merge base (commit B or C) is picked. +# It should have one of those two, which comes out +# to seven lines. +test_expect_success 'diff with two merge bases' ' + git diff br1...master >tmp 2>err && + test_line_count = 7 tmp && + test_line_count = 1 err +' + +test_expect_success 'diff with no merge bases' ' + test_must_fail git diff br2...br3 >tmp 2>err && + test_i18ngrep "fatal: br2...br3: no merge base" err +' + +test_expect_success 'diff with too many symmetric differences' ' + test_must_fail git diff br1...master br2...br3 >tmp 2>err && + test_i18ngrep "usage" err +' + +test_expect_success 'diff with symmetric difference and extraneous arg' ' + test_must_fail git diff master br1...master >tmp 2>err && + test_i18ngrep "usage" err +' + +test_expect_success 'diff with two ranges' ' + test_must_fail git diff master br1..master br2..br3 >tmp 2>err && + test_i18ngrep "usage" err +' + +test_expect_success 'diff with ranges and extra arg' ' + test_must_fail git diff master br1..master commit-D >tmp 2>err && + test_i18ngrep "usage" err +' + +test_done |